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Java

Posted by Michael Partridge
Michael Partridge
7,129 Points

Why is it bad practice to have the user directly edit the modifier?

At first we were modifying the public mCharacterName in the Pez example. When we changed it to private it required we create a method and constructor. This to me seems like excess coding. Why is it bad practice to change the modifier when in reality we are changing it, just not directly?

2 Answers

Craig Dennis
STAFF
Craig Dennis
Treehouse Teacher
Craig Dennis
Craig Dennis
Treehouse Teacher

By setting it private and only setting it in the constructor, after it's been initialized, no one externally can modify it. This is just like real life. Can't change Pez character heads after they have been created. This is what we want to convey to users of the class. They will not be able to change the character after it is created.

This is a very light walk into the world of encapsulation, an Object Oriented Programming principle. You should expose really only what you want to have exposed.

That make more sense?

Michael Partridge
Michael Partridge
7,129 Points

Awesome! So like you said it's more to convey restrictions to the user than anything. That makes a lot of sense moving forward. Thanks Craig!

Josh English
Josh English
1,880 Points
Josh English
Josh English
1,880 Points

Using a getter is usually paired with a setter, which allows you to control the input beyond what the type declaration demands. A user could try to set the number of Pez to be more than is acceptable, or overcharge the GoKart battery, or set these values to negative numbers. These could all be fatal flaws.